The importance of exercise on fat loss, is it useless to take fat burners on sedentary days?
I have read that caffeine, yohimbine, EC, etc. metabolize fat and exercise is required to oxidize the fat.

Is there are large difference in fat loss if one consumes fat burners and does no exercise vs supps + exercise?

Personally there is a difference, but there are days where I don't do much yet still take fat burners and would want to know their effectiveness.

There will be a difference, the yohimbine will help free up the fat but it will just stay in circulation in your body until its needed to be burned. That's why some low-medium intensity cardio is recommended so you use the fat as fuel.

Using yohimbine on a IF type plan would probably still be beneficial without exercise, taking it in the fasted state will free up fat and your body will be primarily using fat as fuel since you're still fasted. This is just conjecture on my part.